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Identify a Study Area and Delineate a Basin

Modified on: Thu, 28 Sep, 2017 at 11:22 AM

After a state or region has been selected, the Select a State/Region banner will turn gray and the name of the selected state or region will display in the banner. To the right of the state name is a black circle with an “i” in it . Clicking on this symbol will open the About window, with the State/Regional Info tab for the selected state, as described above.

The Identify a Study Area banner will then turn dark blue. Its associated panel will open, with a gray text box at the top, indicating that the map needs to be at zoom level 15 or greater before the Delineate tool can be used, and below that will be the green Delineate tool button. After zooming to at least zoom level 15, a gridded representation of the stream network will appear on the map in dark blue. Click on the Delineate button and then on a point on the stream grid. Initially, StreamStats will place a blue pointer at the selected location and a small pop-up window will appear above the point, providing the latitude and longitude of your selected point. Also, a series of notifications will appear and then disappear towards the bottom right of the map giving feedback on the progress of the processing to determine the drainage-basin boundary for your selected site. Eventually, the screen will redraw, showing the blue pointer at the selected site and its drainage basin highlighted in yellow. On the sidebar, the Identify A Study Area banner will indicate “BASIN DELINEATED.” It is good practice at this point to zoom in and pan around the basin boundary to assure that StreamStats has delineated it accurately.

The Identify A Study Area panel will now display four or more buttons, depending on the state or region in which the selected site is located. The buttons that always will appear include Clear Basin, Edit Basin, Download Basin, and Continue. Below the Edit Basin button, some states or regions will have a State/Region Specific Functions panel that includes additional buttons to perform tasks that are unique to the selected area, as explained in the State/Region Specific Functions section below. Clicking on Clear Basin will cause the delineated basin to disappear from the map. The Identify A Study Area banner will then turn blue again and the Delineate button will re-appear, allowing you to select a new location. Editing a basin is explained below. Clicking on the Download button provides options for downloading the basin in formats that can be used by other GIS applications, including GeoJSON, Shapefile, and ESRI file geodatabase formats. If the basin is downloaded at this point the file will contain the geospatial data for the basin. Users will also have the opportunity to download the basin after computing basin characteristics and estimating streamflow statistics, at which point the computed values will be included as attributes in the downloaded files. Clicking on Continue will activate the Select Scenarios banner and open its panel.